Zoom lens barrel

ABSTRACT

A zoom lens barrel includes a fixed frame, a rotary frame, a moving frame that moves in an optical axis direction with the rotary frame, a float key that is restricted from rotating and moves, an inner cam frame that has a cam follower, is rotationally driven by the rotary frame, and moves in the optical axis direction, a guide frame that has a cam follower, and moves in the optical axis direction, an outer cam frame moves in the optical axis direction with the guide frame, and moves relatively with respect to the guide frame, a second group zoom frame that holds a second group lens, has a cam follower, is restricted from rotating around the optical axis, and moves in the optical axis direction, and a first group zoom frame that holds a first group lens, has a cam follower, and moves in the optical axis direction.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Application No.2009-254306 filed in Japan on Nov. 5, 2009, the contents of which areincorporated herein by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom lens barrel, and moreparticularly, to a zoom lens barrel having an advanceable andretractable lens frame.

2. Description of the Related Art

In recent years, digital cameras have showed tendencies to be enhancedin performance and to be more compact and slimmer. Accordingly, in orderto be adapted to the tendencies, the zoom lens barrels incorporated inthe cameras are in such a state as to be desired to have highmagnifications and shorter barrel lengths in the lens optical axisdirections in the collapsed state. As the above described zoom lensbarrel, for example, the one having an advanceable and retractablebarrel structure formed by a plurality of stages is generally applied.

The above described zoom lens barrel includes a fixed frame placed at anoutermost periphery, a plurality of movable frames which are fitted inan inner portion of the fixed frame by being superimposed thereon towardan inner peripheral side, and are advanceable and retractable in anoptical axis direction, and a plurality of lens holding frames (lensframes) supported by an inner peripheral portion of any of the abovedescribed plurality of movable frames. The above described plurality ofmovable frames are provided with cam means formed by cam grooves and camfollowers for frame advancing and retracting drive. The above describedplurality of advancing and retracting frames are sequentially drawn outat the time of zooming, and the above described holding frames supportedby the advancing and retracting frames at the inner peripheral sideperforms advancing and retracting movement in the optical axisdirection. As the zoom lens barrel having such a configuration, there isthe one disclosed by Japanese Patent Application Laid-Open PublicationNo. 2005-173413, for example.

SUMMARY OF THE INVENTION

The present invention includes a fixed frame, a rotary frame thatrotates around an optical axis with respect to the fixed frame,

a first rectilinearly moving member that is restricted from rotatingaround the optical axis with respect to the fixed frame, and moves in anoptical axis direction with the rotary frame,

a second rectilinearly moving member that is restricted from rotatingaround the optical axis by the first rectilinearly moving member, andmoves in the optical axis direction,

first cam means including the rotary frame and the first rectilinearlymoving member,

second cam means including the rotary frame and the first rectilinearlymoving member,

a first cam frame that has a first cam follower which engages with andslides in contact with the first cam means, rotates with the rotation ofthe rotary frame, and moves in the optical axis direction,

third cam means including the second rectilinearly moving member and thefirst cam frame,

a third rectilinearly moving member that has a second cam follower whichengages with and slides in contact with the second cam means, isrestricted from rotating around the optical axis, and moves in theoptical axis direction,

a second cam frame that is fitted on the first cam frame, is restrictedfrom relatively rotating around the optical axis by the first cam frame,is movable in the optical axis direction with respect to the first camframe, moves in the optical axis direction with the third rectilinearlymoving member, and is provided rotatably with respect to the thirdrectilinearly moving member,

rotation transmitting means that transmits rotation of the first camframe to the second cam frame,

a first lens frame that holds a first lens which is a part forming azoom lens system, has a third cam follower which engages with and slidesin contact with the third cam means, is restricted from rotating aroundthe optical axis by the second rectilinearly moving member, and moves inthe optical axis direction with rotation of the first cam frame,

fourth cam means configured by the third rectilinearly moving member andthe second cam frame, and

a second lens frame that holds another second lens different from thefirst lens of the zoom lens system, has a fourth cam follower whichengages with and slides in contact with the fourth cam means, and movesin the optical axis direction with rotation of the second cam frame.

The advantages of the invention will become more apparent from thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing a part of a zoom lensbarrel of one embodiment of the present invention;

FIG. 2 is an exploded perspective view showing another part of the zoomlens barrel of FIG. 1;

FIG. 3 is an exploded perspective view of a fixed frame and a zoom driveunit applied to the zoom lens barrel of FIG. 1;

FIG. 4 is an exploded perspective view of a zoom motor and a slit plateapplied to the zoom lens barrel of FIG. 1;

FIG. 5 is a perspective view of a state in which a slit plate ispress-fitted and fixed to the zoom motor of FIG. 4;

FIG. 6 is a perspective view of a state in which a gear box is attachedto the zoom motor of FIG. 4;

FIG. 7 is a front view of the state in which the gear box is attached tothe zoom motor of FIG. 4;

FIG. 8 is a vertical sectional view along a photographing lens opticalaxis in a collapsed state of the zoom lens barrel of FIG. 1;

FIG. 9 is a vertical sectional view along the photographing lens opticalaxis in a wide state of the zoom lens barrel of FIG. 1;

FIG. 10 is a vertical sectional view along the photographing lensoptical axis in a zoom standard state of the zoom lens barrel of FIG. 1;

FIG. 11 is a vertical sectional view along the photographing lensoptical axis in a telescopic state of the zoom lens barrel of FIG. 1;

FIG. 12 is an enlarged vertical sectional view showing an engaging stateof a rotary frame, a guide frame, and a first group zoom frame and anouter cam frame in the zoom lens barrel of FIG. 1;

FIG. 13 is an enlarged vertical sectional view showing an engaging stateof the rotary frame, a moving frame, and the guide frame and the outercam frame in the zoom lens barrel of FIG. 1;

FIG. 14 is a development of a fixed frame inner peripheral surface inthe zoom lens barrel of FIG. 1;

FIG. 15 is a development of a moving frame inner peripheral surface inthe zoom lens barrel of FIG. 1;

FIG. 16 is a development of a rotary frame inner peripheral surface inthe zoom lens barrel of FIG. 1;

FIG. 17 is a development of an outer cam frame outer peripheral surfacein the zoom lens barrel of FIG. 1;

FIG. 18 is a development of an inner cam frame inner peripheral surfacein the zoom lens barrel of FIG. 1;

FIG. 19A is a view showing an arrangement of a first to a fourth lensgroups when the zoom lens barrel of FIG. 1 is in a telescopic state;

FIG. 19B is a view showing the arrangement of the first to the fourthlens groups when the zoom lens barrel of FIG. 1 is in a standard state;

FIG. 19C is a view showing the arrangement of the first to the fourthlens groups when the zoom lens barrel of FIG. 1 is in a wide end state;and

FIG. 19D is a view showing the arrangement of the first to the fourthlens groups when the zoom lens barrel of FIG. 1 is in a collapsed state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A zoom lens barrel 1 that is one embodiment of the present invention isincorporated in, for example, a digital camera or the like, and is acollapsible type zoom lens barrel which is configured to be displaceableto a position of a photographing state capable of photographing in whicheach barrel is drawn out along the direction of the optical axis of thephotographing optical system, and a position of a collapsed state whichis a non-photographing state, in which the above described barrel isdrawn in and housed inside a fixed frame.

In the following description, an optical axis of a photographing opticalsystem in the zoom lens barrel 1 is set as an optical axis O.

Further, in the direction along the optical axis O, a subject side isset as a front, and an image forming side (namely, an image pickupdevice side) is set as a rear. A direction in which each barrel movesforward in the zoom lens barrel 1 is set as a drawing-out direction, anda rotating direction of each barrel is shown by the rotating directionseen from the front side. Further, a lateral direction is shown by thedirection seen from the front side.

As shown in FIGS. 1 and 2, the zoom lens barrel 1 includes a fixed frame2 which is fixed to the camera main body, a rotary frame 3 which issupported by the fixed frame 2, rotationally, and advanceably andretractably driven, and includes first cam means and second cam means, amoving frame 4 that is a first rectilinearly moving frame which advancesand retracts in the direction of the optical axis O with the rotaryframe 3 in a rotation restricted (namely, rotation inhibited) state, andincludes the first and the second cam means, an inner cam frame 9 thatis a first cam frame which rotates with the rotary frame 3, performsadvancing and retracting movement in the direction of the optical axisO, and includes third cam means, a float key 5 that is a secondrectilinearly moving frame which performs advancing and retractingmovement in the direction of the optical axis O with the inner cam frame9 in the rotation restricted state, and includes the third cam means, asecond group zoom frame 11 that is a first lens frame which supportstherein a second group frame 13 and a shutter frame 12, and performsadvancing and retracting movement in the direction of the optical axis Oin the rotation restricted state, a guide frame 6 that is a thirdrectilinearly moving frame which performs advancing and retractingmovement in the direction of the optical axis O in the rotationrestricted state, and includes fourth cam means, an outer cam frame 7that is a second cam frame which performs advancing and retractingmovement in the direction of the optical axis O with the guide frame 6in the rotation restricted state, and includes the fourth cam means, afirst group zoom frame 8 that is a second lens frame which performsadvancing and retracting movement in the direction of the optical axis Oin the rotation restricted state, a first group cap unit 20 whichcontains a lens barrier, a third group frame 14 that is a focus lensframe which is driven to advance and retract in the optical axisdirection at a focusing time and a collapsing operation time, a fourthgroup frame unit 15 which is fixedly supported by a rear surface portionof the fixed frame 2, and an image pickup unit 16 which is fixedlysupported on a rear surface side of the fourth group frame unit 15. Thezoom lens barrel 1 further includes a zoom drive unit 17 and a focusdrive unit 18 as a barrel drive section, and a first group lens 61 thatis a second lens of a zoom lens system held by the first group zoomframe 8, a second group lens 62 that is a first lens of the zoom lenssystem held by the second group frame 13, a third group lens 63 that isa focus lens held by the third group frame 14, a fourth group lens 64held by a fourth group frame 32, a shutter blade 65 held by the shutterframe 12, and a shutter actuator 66, as a photographing optical system.

The fixed frame 2 has a cylinder inner peripheral portion, and in theinner peripheral portion, has a cam groove 2 a in which an inclined camgroove portion inclined relative to the optical axis O, and acircumferential groove portion formed along a circumference areconnected, and a rectilinearly moving groove 2 b formed in the directionalong the optical axis O (FIG. 14).

Further, the zoom drive unit 17 for performing zooming drive of thephotographing optical system is placed in a unit housing section 2 d atan upper right portion of the outer periphery of the fixed frame 2, andthe focus drive unit 18 for performing focusing drive of thephotographing optical system is placed in a unit housing section 2 e atan upper left portion of the outer periphery.

The zoom drive unit 17 includes a gear case 44, a zoom motor 41 as azoom drive actuator, a worm wheel (worm gear) 45, gears 46 and 47, and along gear 48 as shown in FIG. 3. A worm (worm gear) 42 and a slit plate43 having six blades 43 c for detecting a motor rotational amount arefixed to an output shaft 41 c of the zoom motor 41.

The zoom drive unit 17 is assembled to the gear case 44 as shown in FIG.6, and thereafter, the gear case 44 is fitted in the unit housingsection 2 d of the fixed frame 2.

When the zoom motor 41 is attached to the gear case 44 as shown in FIG.6, screws 49 and 50 are inserted into screw holes 41 a and 41 b on thefront surface portion of the motor main body, and are fastened with adriver (not illustrated) inserted through gear driver insertion holes 44b and 44 a (FIGS. 4 and 6). At this time, in the state in which the slitplate 43 as well as the worm 42 are attached to the output shaft 41 c ofthe zoom motor 41, the blades 43 c of the slit plate 43 interfere withdriver insertion at the time of fastening the screws. Especially whenthe number of blades 43 is large, the screw-fastening operation becomesdifficult. In the present embodiment, the number of blades is six (FIG.7).

Thus, in the present embodiment, as the slit plate 43, the slit platewhich is provided with a cutout portion 43 b at a side of a shaft hole43 a is applied as shown in FIG. 4. The zoom motor 41 is first attachedto the gear case 44 by the screws 49 and 50 with only the worm 42 fixedto the output shaft 41 c. Thereafter, the slit plate 43 is inserted fromthe side of the output shaft 41 c at the motor main body side of theworm 42 through the cutout portion 43 b, and press-fitted (FIG. 6). Morespecifically, the cutout space in the cutout portion 43 b, which issmaller than the diameter of the output shaft 41 c of the motor isforcefully expanded, and the slit plate 43 is fitted. The output shaft41 c of the motor and the slit plate 43 are fitted to each other byso-called elastic fitness. The end portion at the motor main body sideof the worm 42 is provided with a locking projection 42 a for whirl stopwhich is engaged with the cutout portion 43 b of the slit plate 43. As aresult, the output shaft 41 c, the worm 42 and the slit plate 43 arebrought into an integrally rotatable state.

The gear case 44 in which the zoom motor 41, the gear 46 and the likeare incorporated is fixed to the unit housing section 2 d of the fixedframe 2 by screws 58 and 59 inserted through screw insertion holes 44 cand 44 d of the gear case 44, through screw insertion holes of the fixedframe 2. The long gear 48 is inserted into a long gear housing chamber 2f in a state in which the long gear 48 is meshed with the gear 47.

Rotation of the zoom motor 41 in the aforementioned zoom drive unit 17is transmitted to the long gear 48 from the worm 42 through the wormwheel 45 and the gears 46 and 47.

The focus drive unit 18 includes a focus motor 51 as a focus driveactuator, a unit support plate 52, a feed screw 56 and a guide shaft 53which are supported by the unit support plate 52, gears 54 and 55, and anut 57 screwed onto the feed screw 56.

The focus drive unit 18 is incorporated in the unit housing section 2 eof the fixed frame 2. Rotation of the focus motor 51 is transmitted tothe feed screw 56 through the gears 54 and 55, and the nut 57 performsadvancing and retracting movement along the direction of the opticalaxis O by rotation of the feed screw 56.

The third group frame 14 holds the third group lens 63, and is housed atthe rear side of the inner peripheral portion of the fixed frame 2. Thethird group frame 14 has a guide shaft hole 14 a in which the guideshaft 53 of the focus drive unit 18 is slidably fitted, and a guideprojection portion 14 b which is slidably engaged in the rectilinearlymoving groove 2 c of the fixed frame 2.

The third group frame 14 is supported to be advanceable and retractablein the direction of the optical axis O by the guide shaft 53 and therectilinearly moving groove 2 c, and is driven to advance and retract inthe direction of the optical axis O by the focus drive unit 18 via thenut 57 at the time of focusing.

The fourth group frame unit 15 includes a fourth group frame bottomplate 31, and a fourth group frame 32 which is fixed to a front surfaceportion of the bottom plate 31 and holds the fourth group lens 64. Thefourth group frame bottom plate 31 is fixed to a rear end surface of thefixed frame 2 by a screw.

The image pickup unit 16 includes an image pickup unit bottom plate 33,an image pickup device unit 34 including a protection glass, an opticalsystem filter, an image pickup device and the like, and a connectingflexible circuit board 35. The image pickup unit bottom plate 33 isfixed in a state overlaid onto a rear surface of the fourth group framebottom plate 31 at a rear side of the fixed frame 2.

The rotary frame 3 is a cylindrical frame member with both ends openedin the direction of the optical axis O, and the cylinder section outerperiphery of the rotary frame 3 is fitted in the cylinder section innerperiphery of the fixed frame 2 in the rotatable, and advanceable andretractable state. At the rear portion of the outer periphery of therotary frame 3, a cam follower 3 b which is slidably fitted in the camgroove 2 a of the fixed frame 2 and a gear section 3 a meshed with thelong gear 48 are formed.

A cam groove 3 c that is a first cam groove (second cam means) which isinclined relative to the optical axis O, and a rectilinearly movinggroove 3 d that is a first rectilinearly moving groove (first cam means)formed in the direction along the optical axis O are provided in theinner peripheral portion of the rotary frame 3, and a circumferentialgroove 3 e along the circumferential direction is provided in a frontend portion of the inner periphery of the rotary frame 3 (FIG. 16).

When the zoom lens barrel 1 is set up to the photographing state fromthe collapsed state, the long gear 48 is rotationally driven by the zoommotor 41. The rotary frame 3 is rotationally driven through the gearsection 3 a, and is drawn out toward the front from the collapsedposition via the cam follower 3 b by the cam groove 2 a to reach thewide position in the photographing state. Thereafter, when the long gear48 is further rotationally driven in the same direction, the camfollower 3 b moves along the circumferential direction on the cam groove2 a, and the rotary frame 3 rotationally moves to the telescopicposition without advancing or retracting in the direction of the opticalaxis O.

As shown in FIG. 14, the cam follower 3 b moves to cam follower relativepositions 3 bc, 3 bw and 3 bt on the cam groove 2 a of the rotary frame3 when the zoom lens barrel 1 is switched to the collapsed state, thewide state and the telescopic state.

The moving frame 4 is a cylindrical frame member with both ends openedin the direction of the optical axis O, and the cylinder section outerperiphery of the moving frame 4 is fitted in the cylinder section innerperiphery of the rotary frame 3 to be relatively rotatable and in arotation restricted (rotation inhibited) state. At the outer peripheralportion of the rear end of the moving frame 4, a guide projectionportion 4 a which slidably engages with the rectilinearly moving groove2 b of the fixed frame 2 and is provided to project outward, and aprojection portion 4 e which is along the outer peripheral portion ofthe front end portion and slidably engages with the circumferentialgroove 3 e of the rotary frame 3 are provided, and at thecircumferential cylinder section, a cam groove 4 d which is a groovewhich penetrates through the inner and outer peripheries, and is asecond cam groove (first cam means) inclined in the direction of theoptical axis O, and rectilinearly moving grooves 4 b and 4 c which aresecond rectilinearly moving grooves (second cam means) along thedirection of the optical axis O are provided (FIG. 15).

The moving frame 4 is restricted (inhibited from rotating) from rotatingby the rectilinearly moving groove 2 b of the fixed frame 2, and isbayonet-coupled to the rotary frame 3 in a relatively rotatable state bythe projection portion 4 e and the circumferential groove 3 e.Accordingly, when the rotary frame 3 rotates and advances and retracts,the moving frame 4 performs advancing and retracting movement in theoptical axis direction with the rotary frame 3 in the rotationrestricted state.

The inner cam frame 9 is a frame member in a cylindrical shape with bothends opened in the direction of the optical axis O, is fitted in theinner peripheral portion of the outer cam frame 7, rotates together (inthe state in which relative rotation is restricted), with both endsopened in the direction of the optical axis O, and advances and retreatsin the direction of the optical axis O. The inner cam frame 9 has a camfollower 9 b that is a first cam follower provided at an outerperipheral rear portion to project outward, a guide projection 9 aintegrally provided at an outer distal end of the cam follower, and arectilinearly moving guide projection 9 e in a linear shape that isrotation transmitting means along the direction of the optical axis O atthe outer peripheral portion. Further, the inner peripheral portion ofthe inner cam frame 9 is provided with two cam grooves 9 c as third camgrooves (third cam means) inclined with respect to the optical axis O,and a pair of cam grooves 9 da and 9 db, a circumferential groove 9 falong the circumferential direction, and a relief section 9 g at thetime of the second group frame 13 being rotated into the retractposition (FIG. 18).

The cam follower 9 b of the inner cam frame 9 slidably engages with thecam groove 4 d of the moving frame 4, and the guide projection 9 ainserted through the cam groove 4 d of the moving frame 4, and slidablyengages with the rectilinearly moving groove 3 d of the rotary frame 3.Accordingly, the inner cam frame 9 advances and retracts in thedirection of the optical axis O relatively to the moving frame 4 whilerotating with the rotary frame 3.

As shown in FIG. 15, when the zoom lens barrel 1 is switched to thecollapsed state, the wide state and the telescopic state, the camfollower 9 b moves to the cam follower relative positions 9 bc, 9 bw and9 bt on the cam groove 4 d of the moving frame 4.

The float key 5 is a frame member formed into a disk shape having anopening in a center, the disk-shaped portion is fitted in the movingframe 4, and advances and retreats in the direction of the optical axisO in the rotation restricted state. The float key 5 is provided with aguide projection portion 5 a projected to the outside of the disk-shapedportion, a projection portion 5 a′ which is paired with the guideprojection portion 5 a and projects at the disk-shaped outer periphery,two rectilinearly moving guides 5 b in straight line shapes that arethird cam means projected forward along the direction of the opticalaxis O, and a projection 5 c which is projected to an outer peripheralside at the outer peripheral portion of the rectilinearly moving guide 5b. A light shielding plate is pasted on the disk-shaped portion of thefloat key 5.

The guide projection portion 5 a of the float key 5 slidably engageswith the rectilinearly moving groove 4 b of the moving frame 4. Further,the projection portion 5 a′ is gently fitted on the rectilinearly movinggroove 4 c of the moving frame 4, and shields an unwanted light enteringfrom the rectilinearly moving groove 4 c from the front of the barrelframe to a certain degree. The rectilinearly moving guide 5 b penetratesthrough the inner peripheral portion of the inner cam frame 9, and theprojection 5 c on the rectilinearly moving guide 5 b slidably engageswith the circumferential groove 9 f of the inner cam frame 9 in thepenetrated state. Accordingly, the float key 5 advances and retracts inthe direction of the optical axis O in the state integrated with theinner cam frame 9 while being restricted from rotating by the movingframe 4.

The second group zoom frame 11 is formed of a cylindrical frame member,and its outer peripheral portion is fitted in the inner peripheralportion of the inner cam frame 9 to be relatively rotatable. Inside thesecond group zoom frame 11, the second group frame 13 is advanceable andretractable perpendicularly to the photographing optical path, and issupported in the rotatable state at the advance position and retractposition, and further, the shutter frame 12 is supported in the stateurged by a spring toward the rear side in the advanceable andretractable state in the direction of the optical axis O, behind thesecond group frame 13.

On the left and the right of the outer peripheral portion of the secondgroup zoom frame 11, a rectilinearly moving groove 11 c along thedirection of the optical axis O, two cam followers 11 a as third camfollowers, and a paired two cam followers 11 ba and 11 bb, which arearranged along the direction of the optical axis O, are provided.Further, at the inner peripheral portion, a support shaft (notillustrated) which rotatably supports the second group frame 13 and isparallel with the optical axis O is provided.

The rectilinearly moving guide 5 b of the float key 5 is slidablyinserted through the rectilinearly moving groove 11 c, the cam follower11 a engages with the cam groove 9 c of the inner cam frame 9, and thecam followers 11 ba and 11 bb are engaged with the cam grooves 9 da and9 db, whereby the second group zoom frame 11 is fitted in the innerperipheral portion of the inner cam frame 9. Accordingly, the secondgroup zoom frame 11 advances and retracts in the direction of theoptical axis O by the moving amount that is the result of the movingamount by the cam grooves 9 c and 9 da being added to the respectiverelative moving amounts of the moving frame 4 and the inner cam frame 9,with rotation and advancing and retracting movement of the inner camframe 9 in the state in which the second group zoom frame 11 isrestricted from rotating (inhibited from rotation) by the float key 5.

Among the paired cam grooves 9 da and 9 db, the cam groove 9 da engageswith the cam follower 11 ba from a wide cam follower relative position11 baw to a telescopic cam follower relative position 11 bat without abacklash as shown in FIG. 18 when the zoom lens barrel 1 is in the widestate to the telescopic state, but when the zoom lens barrel 1 is in thecollapsed state, or in the vicinity of the collapsed state, the camgroove 9 da reaches the region of the relief section 9 g, and therefore,is in the non-engaging state in which position restriction is notperformed at a collapsed cam follower relative position 11 bac, that is,a free state. However, the cam groove 9 db is engaged without a backlashin a cam follower relative position 11 bbc corresponding to collapse andin the vicinity of the cam follower relative position 11 bbc, wherebythe second group frame 11 which is in the collapsed state is kept in thestate without a backlash. The cam groove 9 db is engaged with the camfollower 11 bb with a backlash in the regions other than that for thecollapsed state. The cam groove 9 c is engaged with the cam follower 11a without a backlash in the cam follower relative positions 11 ac, 11 awand 11 at all the regions of the collapsed, wide and telescopic states.

A compression coil spring 26 is inserted in a space from the first groupzoom frame 8 at a front end surface of the second group zoom frame 11,so that the second group zoom frame 11 is urged backward and the firstgroup zoom frame 8 is urged forward, respectively, and therefore,backlashes are removed, which are between the cam followers 11 a, 11 ba,11 bb and the cam follower 24 and the respective cam grooves in whichthese cam followers are engaged.

The guide frame 6 is formed by a cylindrical frame member with both endsopened in the direction of the optical axis O, and the cylinder sectionof the guide frame 6 is fitted in the inner peripheral side of thecylinder section of the moving frame 4. A pin member 25 which penetratesthrough the inner periphery from the rear end outer peripheral portionof the guide frame 6 is press-fitted in and fixed to the guide frame 6.At the inner peripheral portion of the guide frame 6, rectilinearlymoving grooves 6 c and 6 b which are third rectilinearly moving grooves(fourth cam means) along the direction of the optical axis O, and acircumferential groove 6 a along the circumferential direction of therear end portion are provided.

In the pin member 25 which is press-fitted in the rear end portion ofthe guide frame 6, a guide pin section 25 c projected to the innerperipheral side of the guide frame 6, a guide pin section 25 b which isprojected to the outer peripheral side, and a cam follower 25 a which isthe second cam follower formed at a distal end portion of the guide pinsection 25 b are formed.

The outer cam frame 7 is formed by a cylindrical frame member with bothends opened in the direction of the optical axis O, the outer peripheralrear end of the cylinder section is located at the rear end portion inthe cylinder section of the guide frame 6, and the outer peripheralportion of the cylinder section is fitted and inserted in the innerperipheral portion of the first group zoom frame 8, and further, theouter peripheral portion of the cylinder section of the inner cam frame9 is fitted in the inner peripheral portion of the cylinder section ofthe outer cam frame 7. The outer cam frame 7 is provided with acircumferential groove 7 b and a projection portion 7 c on an outerperipheral portion at a rear end, a cam groove 7 a that is a fourth camgroove (fourth cam means) which is inclined with respect to thedirection of the optical axis O, on the outer peripheral portion, and arectilinearly moving groove 7 d which is rotation transmitting meansalong the direction of the optical axis O, on an inner peripheralportion. A rectilinearly moving guide projection 9 e of the inner camframe 9 is slidably engaged with the rectilinearly moving groove 7 d ofthe outer cam frame 7, and the outer cam frame 7 is rotatably supportedtogether with the inner cam frame 9, that is, the outer cam frame 7 andthe inner cam frame 9 are supported with relative rotation beingrestricted. The outer cam frame 7 is provided with an abutment inclinedsurface 7 e, which abuts on a driven arm provided at a barrier ring 22,at a front end surface in the direction of the optical axis O, in orderto drive a barrier blade 23 in the closing direction at the time ofcollapse. Further, at a rear side end surface of the outer frame 7, anotch 7 f for avoiding interference with a leg section extending in theoutside diameter direction having the cam followers 9 a and 9 b of theinner cam frame 9 is provided.

The pin member 25 is press-fitted into a pin hole at the rear end of theguide frame 6 from the outer peripheral side, and has a guide pinsection 25 c penetrated through the guide frame 6. The penetrated guidepin section 25 c is slidably engaged with the circumferential groove 7 bof the outer cam frame 7. Further, a guide pin section 25 b and a camfollower 25 a at the projected portion to the outward side of the guideframe 6, of the pin member 25 press-fitted in the guide frame 6 areslidably engaged with the rectilinearly moving groove 4 c of the movingframe 4 and the cam groove 3 c of the rotary frame 3, respectively.

The first group zoom frame 8 is formed by a cylindrical frame member,the outer periphery of the cylinder section is fitted in the innerperipheral portion of the guide frame 6, and the outer cam frame 7 isfitted in the inner peripheral portion of the first group zoom frame 8.A cam follower 24 which is a fourth cam follower projected to the innerperipheral side is press-fitted in and fixed to a rear end of the firstgroup zoom frame 8, a projection portion 8 a, with the cam follower 24being press-fitted, which projects to the outside diameter direction isprovided at the rear end. Further, another projection portion 8 b whichis projected in the outside diameter direction is provided at the sameouter peripheral rear end portion.

The first group zoom frame 8 is fitted to the outer periphery of theouter cam frame 7 with the cam follower 24 engaged with the cam groove 7a of the outer cam frame 7. The first group zoom frame 8 and the outercam frame 7 are fitted in the inner peripheral portion of the guideframe 6 in the state in which the projection portions 8 a and 8 b of thefirst group zoom frame 8 are engaged with the inner peripheral siderectilinearly moving grooves 6 c and 6 b of the guide frame 6, and theprojection portion 7 c of the outer cam frame 7 is engaged with thecircumferential groove 6 a of the guide frame 6.

Accordingly, the guide frame 6 and the first group zoom frame 8 aresupported to be capable of advancing and retracting movement in thedirection of the optical axis O in the rotation restricted (rotationinhibited) state by the moving frame 4, and the outer cam frame 7 issupported to move in the direction of the optical axis O integrally withthe guide frame 6, and is rotationally driven together with the innercam frame 9 by the rotary frame 3. When the guide frame 6 is driven toadvance, retract and rotate by the rotary frame 3, the first group zoomframe 8 advances and retracts in the direction of the optical axis O bythe moving amount which is the result of the moving amount by the camgroove 7 a being added to the respective relative moving amounts of therotary frame 3 and the guide frame 6.

As shown in FIG. 16, the cam follower 25 a of the guide frame 6 moves tothe cam follower relative positions 25 ac, 25 aw and 25 at on the camgroove 3 c of the rotary frame 3 when the zoom lens barrel 1 is in thecollapsed state, the wide state and the telescopic state.

Further, as shown in FIG. 17, the cam follower 24 of the first groupzoom frame 8 moves to the cam follower relative positions 24 c, 24 w and24 t with respect to the cam groove 7 a of the outer cam frame 7 in thecollapsed state, the wide state and the telescopic state of the zoomlens barrel 1. Further, the guide pin section 25 c of the guide frame 6moves to guide pin section relative positions 25 cc, 25 cw and 25 ct onthe circumferential groove 7 b of the outer cam frame 7 in the collapsedstate, the wide state and the telescopic state of the zoom lens barrel1.

The first group cap unit 20 is formed by a first group cap 21, thebarrier ring 22, the barrier blade 23 and a barrier urging spring (notillustrated).

The first group cap 21 has a central opening section 21 a which isopened and closed by the barrier blade 23, and is fitted to a front sideportion of the first group zoom frame 8. The barrier ring 22 issupported at the front surface of the first group zoom frame 8 to berotatable around the optical axis O, and opens and closes the barrierblade 23 by being linked to the rotation of the outer cam frame 7. Thebarrier blade 23 is formed by a pair of barrier blades rotatablysupported by a support shaft 21 b of the first group cap, housed betweenthe first group cap 21 and the barrier ring 22, and is urged in theopening direction by the above described barrier urging spring.

Next, the advancing and retracting operation of the zoom lens barrel 1having the aforementioned configuration will be described.

When the zoom lens barrel 1 is in the collapsed state, the respectivebarrel members are drawn inside the fixed frame 2 in the overlaid stateas shown in FIG. 8. In the collapsed state, the second group frame 13 isrotationally driven by the retreating cam 32 a provided in the fourthgroup frame 32, and a second group lens 62 having an optical axis O′ isretreated from a photographing optical path. Further, the lens barrier23 provided at the distal end portion of the zoom lens barrel is alsoclosed. Further, each of the lens groups (61, 62, 63, 64) when the zoomlens barrel 1 is in the collapsed state is in the state as shown in FIG.19D.

When the zoom lens barrel 1 is set to the wide state capable ofphotographing (state of FIG. 19C) from the above described collapsedstate (state of FIG. 19D), the zoom motor 41 is rotationally driven, andthe rotary frame 3 is rotationally driven clockwise. The rotary frame 3is drawn out in the direction of the optical axis O to the wide positionwhile being rotated by the cam groove 2 a (FIG. 9). At the same time,abutment of the abutment inclined surface 7 e of the outer cam frame 7which abuts on the driven arm of the barrier ring 22 is released, andthe barrier blade 23 is brought into the open state by being linked tothe release.

With rotation and movement of the rotary frame 3, the float key 5 movesin the direction of the optical axis O, the inner cam frame 9 moves inthe direction of the optical axis O while rotating, and with themovement, the second group zoom frame 11 is drawn out to the wideposition. When by drawing-out of the second group zoom frame 11, the camfollower 13 b of the second group frame 13 is rotationally driven alongthe retreating cam 32 a, and is further separated, the second groupframe 13 rotates counterclockwise, and the second group lens 62 entersthe photographing optical path (see FIG. 19C). Further, the shutterframe 12 moves to the position separated relatively to the rear sidewith respect to the second group zoom frame 11 by the urging force ofthe urging spring.

Meanwhile, the guide frame 6 is also drawn out with rotation andmovement in the direction of the optical axis O of the rotary frame 3,and therefore, the first group zoom frame 8 is drawn out to the wideposition via the outer cam frame 7 which rotates and advances andretracts. When the zoom lens barrel 1 is in the wide end (wide endposition) state (state of FIG. 19C), the second group zoom frame 11 isin the position closer to the image pickup device unit 34 than theposition of the first group lens 61, and the rear end surface of theinner cam frame 9 is at the rear side in the direction of the opticalaxis O from the rear end surface of the outer cam frame 7. The front endsurface of the inner cam frame 9 is at the front side in the directionof the optical axis O from the rear end surface of the outer cam frame7, and the front end surface of the inner cam frame 9 is between thefront end surface and the rear end surface of the outer cam frame 7.Further, the front end surface of the second group zoom frame 11 is inthe inner peripheral surface of the inner cam frame 9. At this time, thefront end surface of the rotary frame 3 as an exterior component isforward of the front end surface of the fixed frame 2, and the rear endsurface of the rotary frame 3 is inside the fixed frame 2. The front endsurface of the guide frame 6 is forward of the front end surface of therotary frame 3, and the rear end surface of the guide frame 6 is insidethe rotary frame 3. The front end surface of the first group zoom frame8 is forward of the front end surface of the guide frame 6, and the rearend surface of the first group zoom frame 8 is in the guide frame 6.These components extend in the direction of the optical axis O in theshape of a so-called bamboo shoot.

In another expression, when the lens barrel 1 is at least in a wide endstate, a plurality of cylindrical frame members exposed to the exteriorare in the state in which they are arranged in the optical axisdirection in sequence from the subject side to the image pickup deviceside so that the frames have outside diameters which become graduallylarger from the frame with a small outside diameter at the distal end ofthe lens barrel. In the wide end state, inside the lens barrel, aplurality of cylindrical frame members are in the state in which theyare arranged in the optical axis direction in sequence from the subjectside to the image pickup device side so that the cylindrical framemembers have outside diameters which become gradually smaller from theframe with the small outside diameter at the distal end of the lensbarrel.

When the zoom lens barrel 1 is brought into a zoom standard statecapable of photographing (state of FIG. 19B), or brought into atelescopic state (state of FIG. 19A) after the second group zoom frame11 and the first group zoom frame 8 reach the aforementioned wide endposition capable of photographing (see FIG. 19C), the rotary frame 3 isfurther rotationally driven, and the second group zoom frame 11 and thefirst group zoom frame 8 advance and retract toward the respectivezooming positions (FIGS. 10 and 11). When the zoom lens barrel 1 is in atelescopic state, the second group zoom frame 11 is at the positioncloser to the first group lens 61 than the position of the image pickupdevice unit 34 (see FIG. 19A). Further, the front end surface of theinner cam frame 9 is located at the front side in the direction of theoptical axis O from the front end surface of the outer cam frame 7. Therear end surface of the inner cam frame 9 is located at the rear side inthe direction of the optical axis O from the front end surface of theouter cam frame 7.

In the above described respective zoom states of the zoom lens barrel 1,the third group frame 14 is drawn out via the focus drive unit 18 by therotational drive of the focus motor 51 so that the third group lens 63is located at the focusing position.

In the zoom lens barrel 1 of the present embodiment, the rotary frame 3,the guide frame 6 and the first group zoom frame 8 as the exteriorcomponents extend and contract in the direction of the optical axis O inthe bamboo shoot shape with respect to the fixed frame 2 in accordancewith zooming, whereas the outer cam frame 7 and the inner cam frame 9arranged inside the zoom lens barrel 1 exhibit the opposite bamboo shootstates especially between the wide state (the shortest focal lengthstate) and the zoom standard state (substantially intermediate statebetween the shortest focal length state and the longest focal lengthstate). For reference, the zoom value (focal length) of the zoom lensbarrel 1 of the present embodiment is 4.7 mm to 23.5 mm.

As described above, according to the zoom lens barrel 1 of the presentembodiment, the structure is adopted, in which the two cam frames thatare the first group inner cam frame 9 and the second group outer camframe 7 are fitted to each other, and are inserted and fitted betweenthe inner side of the first group zoom frame 8 and the outer side of thesecond group zoom frame 11, whereby as the cam grooves, only the camgrooves 9 c, 9 da and 9 db for the second group zoom frame 11 areprovided at the inner cam frame 9, and only the cam groove 7 a for thefirst group zoom frame 8 is provided at the outer cam frame 7, and thelength in the direction of the optical axis O of each of the cam frames9 and 7 can be made shorter. Therefore, further reduction in the lengthin the direction of the optical axis O of the zoom lens barrel 1 in thecollapsed state can be realized.

Further, the structure is adopted, which fits the second group zoomframe 11 in the inner peripheral portion of the inner cam frame 9 in thestate capable of penetrating through the inner peripheral portion in thedirection of the optical axis O. Therefore, at the time of zooming, thesecond group zoom frame 11 can be advanced and retracted from theposition extremely close to the image pickup device unit 34 to theposition extremely close to the first group lens 61. In other words,such a long stroke can be adopted, that the second group zoom frame 11advances and retracts from the position in which the rear end surface ofthe second group zoom frame 11 projects rearward from the rear endsurface of the inner cam frame 9 to the position in which the front endsurface of the second group zoom frame 11 projects forward from thefront end surface of the inner cam frame 9 (FIGS. 9 and 11).Accordingly, the moving amount of the second group zoom frame 11 whichmoves in the lens barrel which is significantly drawn out in thedirection of the optical axis O can be sufficiently secured by providingthese outer and inner cam frames 7 and 9, and the high magnificationzooming operation can be realized.

As above, the second group lens 62 can obtain a very large moving amountin the lens barrel.

Further, in the zoom lens barrel 1 of the present embodiment, after thezoom motor 41 is fastened to the gear case 44 by the screws, the slitplate 43 with a cutout portion is attached to the output shaft 41 c bybeing inserted and press-fitted onto the output shaft 41 c from theside. Accordingly, even if the number of blades of the slit plate 43 islarge, the blades do not interfere with the above describedscrew-fastening operation, and the zoom motor 41 can be easily fitted.

The zoom lens barrel according to the present invention enables highmagnification zooming, and therefore, can be used as a zoom lens barrelwhich can be further drawn out in the optical axis direction of thephotographing lens in the zooming state.

The present invention is not limited to the aforementioned embodiment,and various modifications and applications can be carried out in therange without departing from the gist of the invention as a matter ofcourse. Further, the above described embodiment includes the inventionsat the various stages, and various inventions can be extracted by propercombination in a plurality of components which are disclosed. Forexample, even when some of the components are deleted from all thecomponents shown in the above described one embodiment, if the problemto be solved by the invention can be solved, and the effect of theinvention is obtained, the configuration from which the components aredeleted can be extracted as the invention. The invention is notrestricted by a specific embodiment except that the invention is limitedby the accompanying claims.

1. A zoom lens barrel, comprising: a fixed frame; a rotary frame thatrotates around an optical axis with respect to the fixed frame; a firstrectilinearly moving member that is restricted from rotating around theoptical axis with respect to the fixed frame, and moves in an opticalaxis direction with the rotary frame; a second rectilinearly movingmember that is restricted from rotating around the optical axis by thefirst rectilinearly moving member, and moves in the optical axisdirection; first cam means comprising the rotary frame and the firstrectilinearly moving member; second cam means comprising the rotaryframe and the first rectilinearly moving member; a first cam frame thathas a first cam follower which engages with and slides in contact withthe first cam means, rotates with the rotation of the rotary frame, andmoves in the optical axis direction; third cam means comprising thesecond rectilinearly moving member and the first cam frame; a thirdrectilinearly moving member that has a second cam follower which engageswith and slides in contact with the second cam means, is restricted fromrotating around the optical axis, and moves in the optical axisdirection; a second cam frame that is fitted on the first cam frame, isrestricted from relatively rotating around the optical axis by the firstcam frame, is movable in the optical axis direction with respect to thefirst cam frame, moves in the optical axis direction with the thirdrectilinearly moving member, and is provided rotatably with respect tothe third rectilinearly moving member; rotation transmitting means thattransmits rotation of the first cam frame to the second cam frame; afirst lens frame that holds a first lens which is a part forming a zoomlens system, has a third cam follower which engages with and slides incontact with the third cam means, is restricted from rotating around theoptical axis by the second rectilinearly moving member, and moves in theoptical axis direction with rotation of the first cam frame; fourth cammeans configured by the third rectilinearly moving member and the secondcam frame; and a second lens frame that holds another second lensdifferent from the first lens of the zoom lens system, has a fourth camfollower which engages with and slides in contact with the fourth cammeans, and moves in the optical axis direction with rotation of thesecond cam frame.
 2. The zoom lens barrel according to claim 1, whereina cylinder section outer periphery of the rotary frame is at an innerside from a cylinder section inner periphery of the fixed frame, acylinder section outer periphery of the first rectilinearly movingmember is at an inner side from the cylinder section inner periphery ofthe rotary frame, a cylinder section outer periphery of the thirdrectilinearly moving member is at an inner side from a cylinder sectioninner periphery of the first rectilinearly moving member, a cylindersection outer periphery of the second cam frame is at an inner side of acylinder section inner periphery of the third rectilinearly movingmember, and a cylinder section outer periphery of the first cam frame isat an inner side of an inner periphery of the second cam frame.
 3. Thezoom lens barrel according to claim 1, wherein when the zoom lens barrelis located at a wide end position, a rear end surface of the first camframe is rearward of a rear end surface of the second cam frame in theoptical axis direction, and when the zoom lens barrel is at a telescopicposition, a front end surface of the first cam frame is forward of afront end surface of the second cam frame in the optical axis direction.4. The zoom lens barrel according to claim 2, wherein when the zoom lensbarrel is located at a wide end position, a rear end surface of thefirst cam frame is rearward of a rear end surface of the second camframe in the optical axis direction, and when the zoom lens barrel is ata telescopic position, a front end surface of the first cam frame isforward of a front end surface of the second cam frame in the opticalaxis direction.
 5. A zoom lens barrel, comprising: a fixed frame; arotary frame that has a first cam groove and a first rectilinearlymoving groove, and rotates with respect to the fixed frame; a firstrectilinearly moving member that has a second cam groove and a secondrectilinearly moving groove, is restricted from rotating by the fixedframe, and moves in an optical axis direction with the rotary frame; afirst cam frame that has a first cam follower which engages with andslides in contact with the first rectilinearly moving groove and thesecond cam groove, and a third cam groove, and rotates with the rotationof the rotary frame; a second rectilinearly moving member that engageswith the second rectilinearly moving groove, and moves in the opticalaxis direction with rotation of the rotary frame; a third rectilinearlymoving member that has a second cam follower which engages with andslides in contact with the first cam groove, and slides in contact withand engages with the second rectilinearly moving groove, and a thirdrectilinearly moving groove; a second cam frame that has a fourth camgroove, is fitted on the first cam frame, is movable in the optical axisdirection with respect to the first cam frame, moves in the optical axisdirection with the third rectilinearly moving member, and is providedrotatably with respect to the third rectilinearly moving member;rotation transmitting means that transmits rotation of the first camframe to the second cam frame; a first lens frame that holds part oflenses which form a zoom lens system, has a third cam follower whichengages with and slides in contact with the third cam groove, isrestricted and inhibited from rotating by the second rectilinearlymoving member, and moves in the optical axis direction with rotation ofthe first cam frame; and a second lens frame that holds another lensdifferent from the lens of the zoom lens system, has a fourth camfollower which engages with and slides in contact with the fourth camgroove, and moves in the optical axis direction with rotation of thesecond cam frame.
 6. The zoom lens barrel according to claim 5, whereina cylinder section outer periphery of the rotary frame is at an innerside from a cylinder section inner periphery of the fixed frame, acylinder section outer periphery of the first rectilinearly movingmember is at an inner side from the cylinder section inner periphery ofthe rotary frame, a cylinder section outer periphery of the thirdrectilinearly moving member is at an inner side from a cylinder sectioninner periphery of the first rectilinearly moving member, a cylindersection outer periphery of the second cam frame is at an inner side of acylinder section inner periphery of the third rectilinearly movingmember, and a cylinder section outer periphery of the first cam frame isat an inner side of an inner periphery of the second cam frame.
 7. Thezoom lens barrel according to claim 5, wherein when the zoom lens barrelis located at a wide end position, a rear end surface of the first camframe is rearward of a rear end surface of the second cam frame in theoptical axis direction, and when the zoom lens barrel is at a telescopicposition, a front end surface of the first cam frame is forward of afront end surface of the second cam frame in the optical axis direction.8. The zoom lens barrel according to claim 6, wherein when the zoom lensbarrel is located at a wide end position, a rear end surface of thefirst cam frame is rearward of a rear end surface of the second camframe in the optical axis direction, and when the zoom lens barrel is ata telescopic position, a front end surface of the first cam frame isforward of a front end surface of the second cam frame in the opticalaxis direction.